diff: enable autoencode by default

This turns on auto-encode whenever textconv is on and the
--binary option has not been used.

Signed-off-by: Jeff King <peff@peff.net>

Author: peff

diff.c

@@ -5193,6 +5193,8 @@ void repo_diff_setup(struct repository *r, struct diff_options *options)
 
 	options->color_moved = diff_color_moved_default;
 	options->color_moved_ws_handling = diff_color_moved_ws_default;
+
+	options->flags.allow_autoencode = -1;
 }
 
 static const char diff_status_letters[] = {
@@ -5391,6 +5393,9 @@ void diff_setup_done(struct diff_options *options)
 
 	if (options->pathspec.has_wildcard && options->max_depth_valid)
 		die("max-depth cannot be used with wildcard pathspecs");
+
+	if (options->flags.allow_autoencode == -1)
+		options->flags.allow_autoencode = !options->flags.binary;
 }
 
 int parse_long_opt(const char *opt, const char **argv,

diff.h

@@ -194,7 +194,7 @@ struct diff_flags {
 	unsigned dirstat_by_file;
 	unsigned allow_textconv;
 	unsigned textconv_set_via_cmdline;
-	unsigned allow_autoencode;
+	int allow_autoencode;
 	unsigned diff_from_contents;
 	unsigned dirty_submodules;
 	unsigned ignore_untracked_in_submodules;